In order to aim at far away targets, scopes are usually utilized in firearms. These scopes help magnify the view in their sight in order to give a clearer vision of the target. However, this magnification brings along a concession of accuracy. As the scope is used for aiming at far away targets, even a single millimeter deviation of the barrel causes the bullet to deviate dramatically when it reaches the target. In order to increase accuracy in aiming, reticules are utilized. Reticules come in handy when aiming at a far away target as they give a very good idea on how the barrel of the firearm is pointed. However, even the reticules cannot help to aim at very far away targets. When fired, a bullet's trajectory will be affected by the gravity and wind. Thusly, for long flight times, the bullet will noticeably deviate from the center of the reticule. In order to compensate the effect of gravity, the center of the reticule must be shifted upwards from the target aimed.
When using crosshair reticules, the amount of shift in order to compensate the effect of gravity cannot be seen quite clearly as there are no markers, which make seeing the shifted amount possible. In order to overcome this problem, markers have been added to the reticule, which makes determining the shifting amount easier. There are numerous types of markers, one of which utilizes mil-dot.
Mil-dot reticule is a reticule, which utilizes small dots, which are positioned in milliradian intervals. These dots may also be utilized in estimation of the range of target. However, for a scope that has multiple zoom levels, a reticule with a fixed mil-dot interval is not useful as the area spanned by those mil-dots are different between the zoom levels.
There are scopes, which have separate mil-dot reticules with different separations between the mil-dots for every constant zoom level. However, for continuous zoom systems, having a separate mil-dot reticule for every single zoom level is not plausible. A different approach for the scopes with continuous zoom has to be used.
The United States patent document numbered U.S. Pat. No. 6,362,882 discloses a reticule projection system for video inspection apparatus.
The United States patent document numbered US 2005018041 discloses an electronic firearm sight, and method of operating same.